Feasibility Analysis of a Double-Acting Composite Cylinder in High-Pressure Loading Conditions for Fluid Power Applications

Abstract

A preliminary study on a double-acting hydraulic cylinder subject to high-pressure loading conditions (pressure = 350 bar) and with a bore diameter of 300 mm is presented. The substitution of the reference steel cylinder tube with a multi-material tube is investigated. In detail, a solution providing a steel thin inner liner wrapped by carbon composite materials is analytically and numerically tested in terms of weight reduction. The composite lay-up design and the component geometry are built to comply with manufacturing constraints for a relatively high-volume production. The alternative multi-material cylinder is designed to ensure the same expected performance as its steel counterpart. Firstly, the non-conventional hydraulic cylinder was designed by extending Lamé’s solution to composite materials, by adopting the micro-mechanics theory of composites in order to bear the maximum operating pressure by monitoring its radial and axial deformation. The selection of the most appropriate carbon reinforcement was investigated. The influence of the stiffness-to-weight and the strength-to-weight ratio of the reinforcement on the design is discussed. Secondly, finite element analyses were performed to evaluate the occurrence of buckling and the modal response of the actuator considering the fluid and of the cylinder own weight influence. The results confirm the validity of the new cylinder tube design compared to the reference steel component. The proposed barrel weights 80 kg compared to the 407 kg of the reference cylinder, with a weight reduction of ~80%. Furthermore, it has a compact design with a decrease of the barrel outer diameter of ~5.3%.

Overview of Materials Used for the Basic Elements of Hydraulic Actuators and Sealing Systems and Their Surfaces Modification Methods

“…In [ 69 ], the pipe is made from a thin S355 steel insert on the inside and is wrapped with CFRP (Carbon Fiber Reinforced Polymer) on the outside. The use of the insert was to provide the sealing system with appropriate tribological working conditions.…”

“…Apart from ferrous materials, light metals such as Al 7075-T6 [ 63 , 69 ] are also used in the context of this application.…”

“…The steel commonly used for the piston rod can also be 40HM (42CrMo4) [ 42 , 69 , 81 ]. Other materials are 20MnV6 [ 85 ], 19MnVS6, 38MnVS6 [ 1 ], or 30CrNiMo8 [ 70 ].…”

“…The caps are often made of the same material as the cylinder. This can be low carbon steel S355 [ 69 ], S355 JR [ 2 ], or S275 JR [ 63 ]. In [ 20 , 63 ], Al 7075-T6 alloy is additionally proposed for this element.…”

“…Aluminum Al 7075-T6 for glands was used in [ 20 , 63 , 69 ]. In [ 73 ], the application of POM type plastic is mentioned.…”